Hidden population declines revealed by integrating long-term fisheries data with fishers’ knowledge
Year: 2026
Type: article
Abstract: Technological creep, the gradual increase in fishing power due to technological innovation, can mask population declines and bias fisheries assessments, yet information on historical technology adoption is rarely available. Here, we integrate long-term fisheries statistics (1972–2022) with structured interviews with experienced fishers to reconstruct technological change in the Japanese pole-and-line skipjack tuna ( Katsuwonus pelamis ) fishery. We estimate population trajectories over five decades using a Bayesian state-space model with time-varying catchability informed by questionnaire data. Biomass estimates decline substantially when catchability increases over time, by approximately 3.5-fold over the study period, equivalent to about 2.5% annually, relative to models assuming constant catchability. The resulting biomass trajectory indicates that the stock off Japan is below levels compatible with maximum sustainable yield (MSY). Fishers’ perceptions corroborate the inferred decline in skipjack tuna abundance despite apparently stable catch rates. Our findings highlight the importance of incorporating dynamic catchability into population models and provide a scalable framework for correcting for technological creep using fishers’ knowledge.
Source: Communications Sustainability
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
SDG: Life below water
Open Access status: diamond
Funder: Fisheries Agency
OpenAlex ID: W7222935974